HNPK (Hereditary Nasal Parakeratosis) in the Labrador Retriever

Hereditary Nasal Parakeratosis (HNPK)

Hereditary Nasal Parakeratosis (HNPK) is a genetic condition primarily affecting Labrador Retrievers, causing painful cracks and crusts on the nose, often referred to as “crusty nose.” DNA testing can help prevent HNPK by identifying carriers before breeding.

What is HNPK?

HNPK is a genetic disorder that results in abnormal growth of the nasal tissue. Normally, a dog’s nose is smooth and moist, but in dogs with HNPK, the nose becomes dry, crusty, and more susceptible to infections and irritation. The root cause of HNPK is a mutation in the SUV39H2 gene, which is critical for normal skin cell development and keratinization. When mutated, the gene disrupts this process, particularly on the nose. The condition is inherited in an autosomal recessive manner, meaning a dog must inherit the mutated gene from both parents to develop the disorder. Dogs that carry only one copy of the mutated gene are asymptomatic but can pass the gene to their offspring.

Symptoms

Symptoms of HNPK typically manifest in Labradors between 6 and 12 months of age. Key signs include:

• Dry, crusty nose
• Cracks and fissures in the nasal planum
• Secondary infections in the nasal planum
• Pigmentation changes on the nose pad
• Pain and discomfort

The severity of symptoms varies between dogs, and although HNPK cannot be cured, treatments like soothing ointments and infection management can help alleviate discomfort. Your veterinarian can recommend the most effective care.

DNA testing

While there is no cure for HNPK, it can be effectively prevented through responsible breeding practices. DNA tests allow breeders to reduce the incidence of this painful condition in future generations of Labradors. This can be done by mating two dogs of which at least one parent is HNPK-free, ensuring that puppies will not develop the disorder.

Relevant tests

• H443